Electric controller for electric motors.



PATENTED JUNE 16, 1903.

W, K. LICCETT.' ELECTRIC CCNTRCLLEE ECE ELECTRIC MCTCEs.

APPLICATION FILED DEG. 22, 1902.

5 SHEETS-SHEET 1.

F0 MODEL.

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mi ohms Varens co, Puma-uma., wAsHwCmx n. c4

PATENTED JUNE 16, 1903.

W. K. LIGGETT. ELECTRIC CONTROLLER IOR ELECTRIC MOTORS.

APPLICATION FILED DEO. 22. 1902.

NO MODEL.

5 SHEETS-SHEET 2.

[N VEN T'OR 77T d?. /77M I Allorney No'. 731,375. PATENTED `JUNE 16',1903. W. K. LIGGETT. ELECTRIC CONTROLLER POR ELECTRIC MOTORS.

APPLICATION FILED DBC. 22. 1902.

N0 MODEL. 5 SHEETS-SHEET 3.

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No. 731,375. Y PATENTED JUNE 16, 1903.

' W. K. LIGGETT. 5

ELECTRIC. CONTROLLER FOR ELECTRIC MOTORS.

APPLICATION FILED DEC. 22. 1902.

H0 MODEL. 5 SHEETS-SHEET 4.

WTIVESSES NVENTOR l, f C/l/c/ Me),

No. 731,375. EATENTED JUNE 1C, 1903.

W. K. LLCCETT. ELECTRIC CONTROLLER ECR ELECTRIC MCTCRS.

APPLICATION FILED DEC. 22. 1902.

No MODEL. 'sEEETs-SHEET a.

Wim/55555 /NI/'ENTOR Nar/31,375.

UNITED :STA-'TIES atented June i6, i903.

PATE-NT OFFICE.

W'IIILIAM K. LIGGETT, OF COLUMBUS, OHIO, ASSIGNOR TO THE KINKADE daLIGGETT COMPANY, OF COLUMBUS, OHIO.

ELECTRIC CONTROLLER FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent N o. 731,375, dated June16, 1903.

Application filed December 22,1902. Serial No. 136.261. (No model) To@ZZ whom it may con/cern:

Be it known that I, WILLIAM K. LIGGETT, of Columbus,- in the county ofFranklin and State of Ohio, have invented certain new and usefulImprovements in Electric Controllers for Electric Motors; and I dohereby declare the following to be a full, clear, and exact descriptionof the invention, such as willenable others skilled in the art to whichit ap- Io pertains to make and use the same.

My invention relates to improvements in electric controllers forelectric motors, and particularly adapted for controlling motorsrcquired to be started, stopped, and reversed I5 frequently, notablythose used for elevator service. Heretofore it has been customary tomake such controllers with numerous sliding, rolling, or knife-edgecontacts, which require constant attention to preventthem from burnzoing and sticking, or they have been made with a complicated system ofelectromagnets for their operation, thus very much increasing the dangerof burning out and other troubles attending the use of such devices.

One object of my invention is to provide a simple mechanically operatedcontroller which shall be free from all sliding movements in thecurrent-carrying parts and which shall have these parts so formed as toreduce 3o the burning to a minimum and make it next to impossible forthem to stick or weld into each other.

A further object is to provide simple and eflcient means for reversingswitches before 35 the circuit through the apparatus 'is closed and alsofor insuring the opening of the main circuit before said circuit can bebroken by the opening of said switches.

A further object is to so construct a controller for electric motorsthat the circuit through the same will be closed after the closing ofthe reversing switch and so that switches of the rheostat will beautomatically closed successively after the reversing-switch and theswitches which control the passage of current through the apparatusshall have been closed. y

A further object is to construct a controller of the class abovespecified that after the re- 5o versing-switch and the switch whichcontrols the passage ot' current shall have been successively closed therheostat-switches will be successively closed automatically andgradually to cut out resistance and so that subsequently a switch shallbe automatically closed to cut out a portion of the field-winding of themotor.

VA further object is to provide an electric controller with simple andeiicient means constructed and adapted to operate automat- 6o ically toopen the circuit through the apparatus should the current on the mainline fail from any cause.

A further object is to provide means for preventing the operation of thecontroller if the various switches are not in their proper normalpositions.

A further object is to provide an electric controllerwith meansconstructed and adapted to operate automatically to open the cir; 7ocuit through the apparatus in case the current becomes excessive.

A further object is to provide switches constructed and adapted to openthe circuit through the apparatus in case of failure of the main currentor in case of excessive current and to provide means for locking theseswitches open and maintaining them (or either of them) so locked untilthe switches which control the passage and direction otl the cur- 8orent through the motor and the switches of the rheostat shall have beenmoved to their proper normal starting position. I

A further object is to provide an electrical controller which shall besimple in construction and easy to keep in order and which shall beeffectual in all respects in the performance of all the functionsrequired of it.

With .these objects in view the invention consists in certain novelfeatures of construc- 9o tion and combinations of parts, as hereinafterset forth, and pointed out in'the claims.

In the accompanying drawings, Figure lis an oblique projectionillustrating my invention applied to a compound-wound reversible motor.Fig. 2 is a detail View, partly in section, illustrating one of thecam-operated switches. Fig. 3 is an enlarged detail view illustratingthe coupling between the parts of the shaft. Fig. 1t is an enlargeddetail View roo of the rdevices for driving the shaft which carries thecams for operating the rheostatswitches. Fig. 5 is a View incrosssection through the main contact-switch. Fig. 6 is a transversesection taken at right angles to Fig. 5. Fig. 7 is a sectional Viewillustrating the blow-out magnet. Fig. 8 is a detail View of theno-voltage7 and overload switches and their lockingdevices. Fig. 9l isa- View taken at right angles to FigA Fig. 10 is detail sectional Viewof the locking devices for said switches. Fig. 11 is a diagrammaticalview illustrating the circuits.

1 represents my improved controller, and 2 an'electric motor of thecompound-wound type, having a series winding 3 and a shuntwinding 4, andthese windings are connected with the controller-circuits, ashereinafter explained.

The controller comprises two switchboards 5 and 6, and these constitutetwo sides of a box vcontaining a number of lcoils 8 of resistance-wire.The sides 9 9a of said box are preferably made of iron, while the sides5 6, on which the switch devices are located, may be made of slate orother non-conducting material. The switches on the board 5 aremechanically driven and so arranged as to be under the control of anoperator for effecting the starting, stopping, or reversing of the motorand throwing resistance into and out of the circuit, while the switcheson the board 6 (with the exception of the knife-edge switch at theleading-in terminals) are electrically actuated and more or lesscontrolled by the operation of switches on the board 5. The1nechanically-operated switches on the board 5, though differing inelectrical functions, are identical in construction, and hence a detaildescription of one of them will suffice for all.

In constructing,r each switch on the board 5 I employ an arm or lever 7,pivotally supported near one end in a bracket 9, projecting from abase-plate 10, secured to the board 5. The arm or lever 7 is perforatednear one end for the passage of the stein 11 of a copper or brasscontact-piece 12, disposed under the end ot' the arm or lever. Aconnector 13 is placed on the stem 11 and the contact-piece 12. lts stem11 and connector 13 are electrically separated from the arm or lever bymeans of insulating material 14` The free end of the stem 11 isscrew-threaded for the reception of a nut 15, by means of which thecontact-piece and its coacting parts are rigidly secured in place. Theotherside of the switchconsists of a carbon contact-block 16, with whicha conductor 17 is electrically connected. This contact-block is securedin a holder 1S, and the latter is provided with a spherical enlargement19, seated in a similarly-shaped portion of a socket-piece 20. Thesocket-piece 20 is provided with a shank 21, which passes through theboard 5 and threaded at its end to receive a nut 22. The holder 18,enlargement 19, and shank 21 are made with alined perforations for thepassage of the conductor. From this construction it will be seen thatthe contact-block 1b' will readily adjust itself relatively to thecontactpiece 12 when the latter is pressed against it,

and thus insure a good electrical contact between the parts 12 and 16. Arod 23 is secured to the base-plate 10 and passes loosely through a hole24 in the switch arm or lever 7 and threaded at its outerend for thereception of a nut 25, between which and the switch arm o'r lever acoiled spring 26 encircles the rod and tends normally to move thecontact-piece 12, carried bythe switch-arm, toward the carboncontact-block 16, the tension of said spring being readily adjustable bymeans of the nut 25. The movement of the switch-lever by the spring toclose the contacts 12 1G is resisted and controlled by a earn 27, actingon a roller 28, carried by the short arm of the switch-lever. It will beseen that by means of the cam 27 the switchlever may be permitted by theaction of the spring 26 to turn on its fulcrum to bring thecontact-piece 12 into engagement with the contact-block 16 te close anelectric circuit including these contact devices, or said cam may beturned to positively rock the switchlever in the reverse direction toopen such circuit.

In Fig. 1 of the drawings two rows of switches, such as above describedin detail, are shown on the board 5. Of these the switches 2S 29 and 3031 constitute a reversing-switch, the connectors 13 of the switches 28and 30 being connected with one commutator-brush 32 of the motor by aconductor A 33, and the connectors 13 of the switches 29 and 3l beingconnected Vwith the other commutator-brush 34' by a conductor 35, whilethe contact-blocks 16 of these switches are connected in circuit, ashereinafter more fully explained. The switch 36 of thelower rowconstitutes a pilot-switch for closing the circuit of a main switch 37on the board 6. The switches 3S, 39, 40, and 41 of the upper rowconstitute the rheostat-switches, and the switch 42 is forshort-circuiting a portion (the series coils) of the field-winding ofthe motor to increase the speed of the motor after all the resistanceshall have been cut out.

It is important that the switches on the board 5 shall operate incertain regular order, so as to prevent the opening of the switchcarrying'current to the motor until the circuit including said switchesshall have been first opened. To operate the said switches andaccomplish the result above stated, the devices now to be described areemployed. A'shaft 43 is mounted in suitable bearing on the board 5 andis provided with any suitable device whereby the operator can manipulateit. This shaft comprises two parts 44 45, arranged in alinement witheach other and connected by a coupling 46. This coupling comprises asleeve 47, secured to the section 44 of the shaft and arranged toconstitute a bearing in which the end of section 45 of the shaft canturn, and a pin 4S, secured to the section 45 of the shaft and adaptedto limit the movement of the section 45 independently of the section 44an extent equal to the Width IIO of a slot or .recess 49 in the sleeve47, in which slot or recess the pin 48 moves. The section 45 of shaft 43carries a cam 27, operating the pilot-switch 36, by means of which themain switch 37 is controlled, and the section 44 of said shaft carriescams 27 for operating the reversing-switches. Thesoleofficeofthesection44 of the shaft 43 is to control the movements of thereversing-switches, and since it is desirable that these switches beclosed before the main circuit through the machine is closed and notopened until after the main circuit has been broken the coupling betweenthe sections 44 45 of shaft 43, above described, is employed to providea certain amount of lost motion between said sections 44 45. The cams onthe section 44 of the shaft are so shaped and arranged that theseswitches move in pairs, preferably the switches 28 29 opening while theswitches 30 3l close, and vice versa, so that the current may bereversed in the armature of the motor. The

Asection 45 of the shaft on moving past the center will operate to closeone pair of these switches (the other pair being open) just before thecam 27 on shaft-section 45 closes the pilot-switch 36 and upon returningthe shaft-section 45 to the center will not movev either pair ofreverse-switches; but a return movement of the shaft-section 45 past thecenter of its movement will reverse the positions of thereversing-switches, and thus reverse the direction of current throughthe armature of the motor. The same movement of the shaft-section 45controls the operation of the rheostat-switches io throw resistance intoand out of circuit. The devices by which these results are accomplishedwill now be explained.

` A shaft 49 is mounted in suitable bearings secured to the board 5,said shaft being located above the two-part shaft 43 and in closeproximity to the lower ends of the switches 38 42. The shaft 49 carriesa series of cams 27", so arranged on the shaft as to operate to closethe several switches successively when said shaft is turned. Awrist-plate 50 is also secured to the shaft 49 and provided with aroller 51, which constitutes, in effect, a wristpin. A cam 52 is securedto the section 45 of the two-part shaft 43 and is adapted to engage theroller or wrist-pin 5l on the wristplate 50 for the purpose of drivingthe shaft 49 in one direction. The wrist-plate 50 (and consequently theshaft to which it is secured) is driven in the reverse direction by theweight of the piston 52 and piston-rod 53 of a dashpot 54, connectedwith said wrist-plate, when the cam 52 shall have been vmoved out of thepath of the roller 5l. The cylinder of the dashpot is secured to theboard 5 above the shaft49, and the piston 52a is provided with suitablepacking 54a, held in place by a plate 55. The

speed of the downward movement of the piston of the dash-pot can beYreadily regulated by means of a petcock 56 in the top of the dashpotcylinder, and the free upward movement of said piston will be permittedby a checkvalve 57, also arranged in the top of the dashpot cylinder. Aportion of the cam 52 marks the arc of a circle concentric to theshaft-section 45, and no movement of the wrist-plate on the shaftl 49results by turning said cam through this arc, which should nearlycorrespond with the arc during which the pilotswitch 36 is held open byits cam. This provision will insure that no resistance shall be cut outuntil the main contact has been made and that all the. resistance shallbe cut in before the main contact has been broken, for the switchescontrolled by the cams on the shaft 49 are either for short-circuitingresistance or the series coils of the field-winding ofthe motor. Inordinary practice I use the switches 38, 39, 40, and 4l forshort-circuiting resistance and the switch 42 to short-circuit theseries field-coils. The cams 27b on the shaft 49 are therefore arrangedso that the switches are all open when the roller 5l rests on thecircular arc of the cam 52 and they will close one after the other,beginningwith the switch 38, all being closed when the shaft 49 reachesthe limit of its travel.

From the construction and arrangement of parts above described it willbe seen that the first movement of the section 45 of the twopart shaftby the operator will be to close two of the reversing-switches and thenclose the pilot-switch. The pilot-switch being now closed, the mainswitch 37 will be closed and current will flow through all theresistances and through the reversing switches and motor-windings. Afterthe pilot-switch has been closed a further movement of the shaftsection45 will cause the cam 52 to ride past the roller 5l on the wrist-plate50, thus releasing thelatter and the shaft 49,which carries it, andpermitting the weight of the dashpot plunger and its rod to rotate saidshaft, the downward movement 0f said plunger and rod, and consequentlythe speed of rotation of the shaft 49, being retarded and to an eX- tentcontrolled by the adjustment of the petcock on the dash-pot cylinder. Asthe shaft 49 rotates the switches 38, 39, 40, and 4l will be operatedsuccessively to gradually shortcircuit resistance, and after all theresistance has been short-circuited the switch 42 will close and thusshort-circuit the series coils of the field-windings ofv the motor toincrease the speed of the latter. A reverse movement of theshaft-section 45 will operate to rotate the shaft 49 through the mediumof the cam 52 and wrist-plate 50 to throw in the series field-winding ofthe motor and then successively open the switches 4l to 38 to throw inthe resistance. A further movement of the shaft-section 45 will resultin opening the pilot-switch 36 and the consequent denergizing of thesolenoid which controls the main switch 37. The circuit through theapparatus is now open. IThe operator may now continue to turn theshaft-section 45 in the same direction,which will result in firstopening ICO IIO

IIS

one pair of reversing-switches and closing the other pair and thenclosing the pilot-switch. The eect of these operations will be toreverse the motor after having cut in the resistance, and this withoutmovement of the reversing-switches while they carried current. After themotor has been thus reversed the cutting out of the resistance and theseries field-winding of Ithe motor will be permitted byafurther movementof the shaftsection 45 in the manner before explained.

I have hereinbefore referred to a main switch under the control of thepilot-switch for opening and closing the main circuit through theapparatus. This main switch will now be described in detail.

A U-shaped frame 59, having a fiat back, is secured to the board 6, asshown in Fig. l. A thin brass tube or bushing is driven into this frameand surrounded by a solenoidhelix 6l, comprising an appropriate numberof turns of proper-sized insulated wire, according to the voltage to beused. To make the magnetic circuit more complete, I prefer to cover thetop of the tube 60 with an iron plate 62. The soft-iron core 63 of thesolenoid is fitted to slide freely in the tube 60 and carries at itslower end a cross-head 64. Near its ends the cross-head is perforatedfor the accommodation of socket-pieces 65, electrically separated fromsaid cross-head by means of insulating material 66. The shank 67 of acontact-piece 68 passes through each socketpiece and through a hole inthe bottom of the latter, and between said contact-piece and the bottomof each socket-piece a coiled spring 69 is located. The lower end ofeach shank 67 is threaded for the reception of a nut 70, which normallybears against the bottom of the socket-piece and a connector 7l. Thelower outwardly-projecting arm of the frame 59 is perforated near eachend for the passage of stems 72, each carrying at its lower end a holder73, and each holder and its stem are electrically separated from theframe by means of insulating material 74. A connector 75 is placed oneach stem 72 and insulated from the frame 59, and the connector 75, stem72, and holder 73 are secured in place by means of a nut 76. The holders73 have carbon contact-blocks 77 secured therein by setscrews 78 and arelocated immediately over the metal contact-pieces 68. The mechanism ofthe switch 37 is so proportioned and arranged that when the solenoid isexcited by the closing of the pilot-switch 36 the rising of the core 63will force the metal contactpieces against the carbon blocks 77 andclose the main circuit, at the same time slightly compressing thesprings 69, so that the jam-nuts will be forced away from their bearingagainst the under faces of the socket-pieces 65, thus giving an evenbearing on each side of the switch. The springs 69 also serve to startthe core 63 downwardly when the excitation of the helix of the solenoidceases, and thus prevent the core from sticking on account of residualmagnetism or from other cause. The core and its crosshead are preventedfrom turning and are limited as to the distance they may fall by meansof two rods '78, which pass through holes in the cross-head, andprovided on their lower end with adjustable cushions 79, held in placeby nuts 80, as shown in Fig. 6.

Blow-out magnets 81 will preferably be used to disrupt any arc whichmight be formed between the contacts of the switch 37. These blow-outmagnets might be arranged in various ways; but I prefer the constructionshown in Fig. 7, wherein two core-pieces 82 83 are shown projectingthrough the board 6 and secured in place by set-screws 84. Thecorepieces are connected by a flat iron plate secured at their ends tothem, and a helix 84 is located on one of the core-pieces.

I prefer to provide the apparatus with an ordinary knife-edge switch 85at the leadingin terminals, such a switch` being attached to the board6, as shown in Fig. l, and having its pivoted arms electricallyconnected with other parts of the apparatus, as hereinafter more fullyexplained, the stationary contacts of said switch having the leading-inline-wires 86 87 connected with them.

In order that the circuit of the solenoid controlling the main switch 37shall be automatically opened when for any reason the current in themain line fails, as upon the blowing of a fuse, the stopping of thegenerator, or opening of the switch 85, I provide the switch 88, which Iterm a no-voltage switch. This switch comprises a magnet 89, similar inall respects to the blow-out magnet above described and shown in Fig. 7,and a rocking arm 90, having a weight 90 and carrying a contact-point91, adapted to engage a contactpiece 92, secured to the board 6. Thismagnet is excited by the current in a shunt-circuit, the terminals ofwhich are connected with the pivoted arms of the switch 85 by means ofconductors 93,as shown most clearly in the diagram Fig. 1l. With sucharrangement the magnet 89 will retain the switch 88 closed when theswitch 85 is closed and conditions of the main line are normal. parent,however, that if the switch 88 be opened or should a fuse blow out atany point between the switch 88 and the generator or should the currentin the mainline fail by the stopping of the generatoror from othercause, the magnet of the switch 88 would be immediately denergized andrelease the rocking arm 90. The weight 90n would then cause said arm todrop until a toe 94 at the lower end thereof strikes the board 6 andresulting in separating the contacts 91 92. These contacts are includedin the same circuit which includes the solenoid-helix of the main switchand the pilot-switch, so that when the switch 88 is opened, as abovedescribed, the controlling-solenoid of the main switch will bedenergized and the said main switch permitted to open.

As the switch 88 is also in luv IIC

It is apcluded in the same circuit with the pilotswitch which controlsthe solenoid ofthe main switch, the apparatus cannot be operated tostart the motor as long as the switch 88 is open. Failure of current inthe main line from any of the causes above mentioned might occur whenthe motor is running at full speed and all the resistance cut out ofcircuit. In such case it would result disastronsly, especially to themotor-windings, should the main circuit be again closed while theresistance to all cutout, and hence it is a matter of importance thatthe switches of the controller 'ne brought to normal starting positionbefore current is permitted to enter the motor, and to insure theresetting of the switches by the operator before attempting to againstart the motor I provide means for locking the switch 88 open and to soconstruct and arrange said locking means that the said switch S8 cannotbe closed by the operator until he has first brought the switches on theboard 5 and their operating devices to normal starting position. Theselocking means will now be described in detail.

The rocking arm 90, above referred to, is secured to one end of a shaft.95, revolubly mounted between its ends in abracket 96,se cured to theboard 6. The other endv of this shaft carries a housing 97, in which alatch 98is mounted to move, said latch being provided with a stem 99,projecting upwardly through the housingr and through a hole in the upperend thereof and provided with a pin 100 to limit the downward movementof the latch. The depending head of the latch is beveled and is retainednormally iu and forced to the lower end of its throw by means of acoiled spring 101, located in the housing 97. The shaft 49, whichcarries the cams for operating the rheostat-switches,terininates inproximity to the latch 96, and on the end of this shaft a disk 102,having a beveled periphery and a notch 103, is secured. Vhen theswitches on the board 5 are in their normal starting positions, the disk102 on the.

shaft 49 will be in such position thatits notch 103 will he in alinementwith the latch 9S; but this latch will be removed laterally from thedisk when the switch 86 is closed, as shown in Fig. 10. Suppose now thatthe main circuit should be opened by failure of the current, as aboveexplained, and the switches on the board 5 are in the positions whichthey would assume when the motor is ruiming at full speed. In such casethe switch 8S would be opened, as before explained, and the movement ofthe rocking arm of said switch would cause the shaftI 95 to turn. As theshaft 95 thus turns, the beveled end of the latch .98,engaging thebeveled periphery ot the disk 102, will cause the latch to ride over theperipheryot' the disk and liecome disposed alongside the opposite facethereof, thuslocking the switch 8S open. The

controller cannot now be operated to start the motor, nor will theclosing of the main circuit by the repair ot' a blown fuse or therestarting of the generator operate to supply current to the motor. 'Iheonly wayin which the switch 8S can be uulockedis to bring the disk 102to such position as to aline the notch 103 therein with the latch 98,and this caunot be accomplishedwithoutbringing all the switches on theboard 5 and their operating devices to their normal starting positionwith all. the rheostat-switches open. rlhus to start the motor after thecurrent fails in the main circuit while the resistance is cut out theoperator must first bring the switches on the board 5 to their normalpositions, after which he will be permitted to close the no-voltageswitch 88.

It is desirable also to open the circuit through the apparatus and tothe motor when the currentfor any reason becomes excessive and toprevent the restarting of the motor until the switches shall have beenbrought back to their normal starting positions. For these purposes Iemploy what I term an overload-switch 10%. This switch comprises amagnet 105 of the same construction as that ot' the magnet 89, a rockingswitcharm 106, carrying a contact-point 107, and a contact-piece 108,secu red to the board 6. The contacts of this switch are maintainednormally together by a weight 109, adjustably mounted on an arm 110,projecting from the rocking switch-arm 106. The rocking arm 106 iscarried by a rockshaft 111, and this shaft carries a latch 112, which isthe same in construction and coperates with the disk 102 in the samemanner as has been already fully explained in connection with the latchof the no-voltage switch, the disk 102 being provided with a notch 113for the accommodation of the latch 112. The magnet of theoverload-switch is included in circuit with the main switch, so thatshould the rise of current passing to motorbecome excessive the magnetof the overload-switch will become sufficiently strong to attract itsarmature and open said switch, thus causing the circuit to the motor tobe opened. The switch 104 will he locked open in the same manner asabove explained in connection with switch 88 and can only be closedafter the switches on the board 5 have been brought to their normalpositions, as will be readily understood.

It remains now' to explain more in detail the paths ofthe severalcircuits traversing the apparatus, as shown in the diagram Fig. 11. 'lheknife-edge switch 85 being closed, the closing ot the pilot-switch willestablish a circuit as follows: from one of the pivoted arms of thisswitch by a conductor 114 through the no-voltage switch 88, then byconductor 115 through overload-switch 104, then by wire 116 to andthrough the pilotswitch 36, then by wire 117 to and through thesolenoid-helix of the main switch 37, and from said helix by conductor118 Vto the other side of the knifeedge switch 85, thus completing thecircuit. The solenoid being energized by the passage of current throughthe circuit above described, the contacts of the main switch will bepromptly closed and establish a circuit as follows: from one side of theswitchiS by wire 119 to and through one pair of contacts of the mainswitch 37, then by wire 120 to and through the magnetcoil ofoverload-switch 104, then by wire 121 to and through the several coilsof resistancewire, then by wire 122 to andth rough the seriesfield-coils of the motor, then by wire 123 to one of thecontact-switches, (say the switch 28,) then by wire 33 to one of the commutatorbrushes of the armature through the armature-windings; and thenby wire 35 to another of the reversing-switches, (say the switch 29,)then by a wire 126 to and through the other contacts of the main switch37, and finally by conductor 127 to the other or minus side ofthe switchS5. There willalso be established two shunt-ci rcuitse-namely, onethrough the magnet-coil of the no-voltage switch, which has already beendescribed, and the other through the shunt field-winding of the motorand the blow-out magnet-s. This shunt-circuit may be readily traced asfollows: from the conductor 121 by'wire 12S to and through the shuntfield-coils 4 of the motor and then by wire 129 to one of the contactsof the main switch 37, the circuit of this wire also including the coilsof the blow-out magnets, as clearly shown by the diagram. One side ofcach ofthe switches 3S, 39, 40, and 41 is connected with conductor 121,while the other sides of the switches 38, 39, and 40 are connected Yatdifferent points with the resistancecoils and the other side of theswitch 41 is connected with the wire 122,'so that as the switches 3S to41 close one after the other the resistance will be graduallyshort-circuited, as will be readilyrunderstood. One side ofthe switch 42is also connected with the wire 121, while the other side of said switchis connected with oneside ofroneofthereversing-switchesfor instance,with the switch 31-for the purpose of shortcircniting the series coilsof the motoriield-wimiing when the switch is closed.

As before explained, the switch 42 will be closed after all theresistance shall have been short-circuited and when said switch 42 hasbeen closed the main circuit will be slightly changed from that abovedescribed-that is to say, the current instead of traversing theconductor 122 will after passing from the conductor 121 through theswitch 42 follow a circuit of lower resistance, by wire 130 to one ofthe reversing-switches, thus short-circuiting the series coils of themotor-winding and causing the rotation of the armature to be increased.

It has been Yhereinbefore explained how the no-voltage switch will beautomatically opened if the current on the main line fails from anycause and how the switch will be locked open while the mechanism is inany but its normal starting position. It has also been explained how theoverload-switch will be opened and locked open should the current to themotor become excessive. Now it will be observed that when the shaft 45has been moved to its normal starting position and the notches 103 ofthe disk 102 shall have been brought Vinto alinement with the latches 98and 112 the 11o-voltage switch S8 and the overload-switch 104 will beunlocked. As soon as the overload-switch has been thus unlocked theWeighted arm 110 thereon will operate to move said switch and close itscontacts. The 11o-voltage switch will remainunlocked and open until thecircuit through the apparatusshal-l have been closed--as, forinstance,by closing switch S-and as soon as this eccu rs the magnet of theno-voltage switch will be energized and operate automatically to closethe said no-voltage switch. Thus it will be seen that should either ofthe said switches be opened during the operation of the mctor theyiwillbe locked open and afterward automatically released and closed after therheostat and reversing switches shall have been mechanically moved tonormal starting pesition.V

Various slight changes might be made in the details of construction ofmy invention without departing from the spirit thereof or limiting itsscope, and hence I do not wish to limit myself to the precise detailsherein set forth. Y

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, isi 1.' In -an electrical controller, thecombination with a series of switches constituting a reversing-switch,and a circuit-closing switch, of a shaft comprising two sections, camscarried by one cf said sections and arrangedlto operate thereversingswitches in pairs, a cam carried by the other shaft-section foroperating the circuit-closing switch, and a lost-motion deviceconnecting said'shaft-sections.

2. In an electrical controller, the combination with a series ofswitches constituting a reversing-switch, and acircuit-closing switch,of`a shaft comprising two sections, cams carried by one of said sectionsand arrangedcto operate the reversingswitches in pairs,YV a cam carriedby the other shaft-section and arranged to operate the circuitclosingswitch, a sleeve having an elongated slot, secured to one of saidshaft-sections and having the otherzshaft-section mounted to turntherein, and aepin secured to said last-mentioned shaftsection andarranged to move in the elongated slotin the sleeve. c

3. In an electrical controller, the combination of a series of switchesconstituting a reversing-switch, each of said switches comprising apivoted arm, a metallic contactpiece'icarried by said arm, a movableholder and a carbon contact-piece carried by said holder, a springnormally tending to press the IIO metallic contact-piece towardthecarbon contactpiece, and means for operating said switches in pairs.

4. The combination in an electrical controller, of a pivoted switch-arm,a spring normally tending to press said arm in one direction, means formoving the arm in the reverse direction, a contactpiece carried by oneend of said arm, a holder mounted to rock and a carbon contact-blockcarried by said holder.

5. The combination in an electrical-controller, of a bracket, an arm orlever pivoted between its ends in said bracket, a contact-piece securedto one end of said arm, a fixed rod passing freely through a hole insaid arm, a spring encircling said rod and bearing against said arm, anut on the rod for adjusting said spring, a carbon contact block, aroller mounted in one end of said arm and a cam engaging said roller forcontrolling the movements of said arm.

G. The combination in an electrical controller, of a pivoted switch armor lever, a contact-piece carried by one end of said arm or lever, afixed socket-piece, a holder having a ball-and-socket connection withsaid socketpiece, a carbon contact-block secured in said holder, aspring for moving the arm or lever in one direction to bring thecontacts together and means for controlling the movements of said arm orlever.

7. The combinationin an electrical controller, of a switch comprising abracket, an arm pivoted between its ends in said bracket, a rod securedto the bracket and passing freely through a hole in the arm, a spring onsaid rod and bearing against the arm, anut on the rod, against which theother end of the spring bears, a contact-plate secured to one end ofsaid arm, a holder, a carbon contact-block secured in said holder, aspherical enlargement projecting from said holder, a socketpiece havinga similarly-shaped socket for the reception of said enlargement, a shankon said socket-piece, a nut on said shank said shank, socket-piece,holder and its spherical enlargement having alined perforations and aconductorpassing through said alined perforations.

8. In an electrical controller, the combination with a manually operatedreversingswitch, and an electricallyoperated main switch, of apilot-switch for controlling the electrical operating means of the mainswitch.

9. In an electrical controller, the combination with 'amanually-operated reversingswitch and an electrically operated mainswitch, of a pilot-switch for controlling the electrical operating meansof the main switch, and means for mechanically operating thereversing-switch and said pilot-switch.

l0. In an electrical controller, the combination with a series ofswitches constituting a reversing-switch, a main electrically-operatedswitch and a pilot-switch included in circuit with theelectrically-operated means of the main switch, of a shaft comprisingtwo sections, cams carried by one section for operating thereversing-switches in pairs, and a cam carried bythe other section ofthe shaft for operating the pilot-switch, and a lost-motion devicebetween the shaft-sections,whereby the reversing-switches will bemanually closed before the pilot-switch is closed and so that thepilot-switch will be opened before any of the reversing-switches areopened.

l1. In an electrical controller, the combination with a mainelectrically-operated switch, a manually-operated reversing-switch and arheostat-switch, of a pilot-switch for controlling the circuit of theelectrically-operated means of the main switch, and mechanical devicesconstructed and adapt-ed to first close the reversing-switch, then -thepilot-switch and then the switches of the rheostat.

l2. In an electrical controller, the combination with a series ofresistance-coils and a series of normally open switches forshort-circuiting the same, of means for releasing said switches, andmeans for automatically closing said switches gradually andsuccessively.

13. In an electrical controller, the combination with a series ofresistance-coils and a series of spring-pressed switches forshort-circuiting the same, of a Shaft, cams secured to said shaft fornormally retaining all of said switches open, said cams so relativelyarranged as to release the switches successively, means for releasingsaid shaft, and means for rotating it.

14:. In au electrical controller, the combination with a series ofresistance-coils and a series of spring-pressed switches forshort-circuiting the same, of a shaft, cams secured to said shaft andrelatively arranged to successively release said switches, a wrist-platesecured to said shaft, a cam for normally preventing movementof saidwrist-plate and for releasing it and means for turning the shaft whenthe wrist-plate shall have been released by the cam.

15. In an electrical controller, the combination with a series ofspring-pressed rheostatswitches, a reversing-switch and acircuitcontrolling switch, of a shaft, cams on the shaft relativelyarranged to successively release the rheostat-switches, a second shaftcomprising two sections, cams secured to one of said sections foroperating the reversingswitch, a cam on the other section for operatingthe circuit-controlling switch, a lostmotion connection between saidshaft-sections, and devices between one of said shaft- Sections and thefirst-mentioned shaft for releasing the latter.

16. In an electrical controller, the combination with a series ofrheostat-switches, a shaft carrying cams for operating said switchessuccessively, a wrist-plate secured to said shaft, of areversing-switch, a circuit-controlling switch, a shaft comprising twosections, a lost-motion connection between said sections, cams securedto one of said sections IOT) IIO

for operating the reversing-switch, a cam carried bythe other sectionfor operating the circuit-controlling switch, another cam carried by thelast-mentioned shaft-section and engaging the wrist-plate on thefirst-mentioned shaft, said last-mentioned cam constructed and arrangedto release the wristplate after the circuit-controlling switch has beenclosed and means for rotating the firstmentioned shaft when thusreleased.

17. In an electrical controller, the combination with a series ofspring-pressed rheostatswitches, of a shaft, a series of cams secured tosaid shaft and relatively arranged to release said switchessuccessively, means for closing the circuit through the rheostat, awrist-plate on said shaft, means for releasing the wrist-plate and shaftafter the circuit has been closed, a dash -pot cylinder provided with apetcock and a check-valve, and a plunger in said cylinder connected withsaid wrist-plate.

18. The combination with an electric motor having a series and a shuntfield-winding, of a rheostat, a series of yswitches therefor, areversing-switch, a switch arranged in a short circuit around the seriescoil of the field-magnet winding, and means for closing thereversing-switches successively and then closing said short-circuitingswitch.

19. The combination in a controller for electric motors, of a mainelectrically-operated switch, a normally closed no-voltage switchincluded in a circuit of the controller with the electrically-operatedmeans of the main switch and electromagnetic means for maintaining saidno-voltage switch normally closed, said last-mentioned electromagneticmeans included in ashunt from the main circuit.

20. The combination in an electric control- 1er, of anelectrically-operated main switch, a pilot-switch included in circuitwith the electricallyoperated means of the main switch, a normallyclosed no-voltage switch included in circuit with the pilot-switch, andan electromagnet for controlling said novoltage switch included in ashunt-circuit.

2l. The combination with an electric controller, of a normally closedswitch included in a controlling-circuit of the apparatus,electricallyactuated means for releasing said switch upon failure ofcurrent on the main line, and means for locking the switch open.

22. The combination with an electrical controller, of a normally closedswitch included in a controlling-circuit of the apparatus,electricallyactuated means for releasing said switch upon failure ofcurrent on the main line, and means for locking the switch open.

23. The combination in an electrical controller, of a mainswitch,electrically-actuated means for operating said switch, a normallyclosed 'switch included in circuit with the electrically operated meansof the main switch, electrically-operated means for releasing saidnormally closed switch upon failure of current on the main line, andmeans for locking the normally closed switch open.

24. The combination with an electric controller, of a normally closedswitch in a controlling-circuit of the apparatus, electrically actuatedmeans in the main circuit constructed and adapted to permitsaid switchto open when there is an abnormal rise of current in the main circuit,and means for locking said switch open. i

25. The combination with an electric controller, of a main switch, apilot-switch for controlling the main switch, a no-voltage switch and anoverload-switch in circuit with the pilot-switch,electrically-controlled means in a shunt-circuit for controlling the p11o-voltage switch and electrically-operated means in the main circuitfor controlling the overload-switch.

26. The combination with an electric controller, of a main switch, apilot-switch for controlling the main' switch, a no-voltage switch andan overload-switch included in circuit with the pilot-switch,electrically-controlled means for the no-voltage switch included in ashunt-circuit, electrically-controlled means for the overload-switchincluded in the main circuit, and locking devices for said no-voltageand overload switches.

27. In an electrical controller, the combination with a rheostat-switchand a shaft carrying means for operating the same, of a novoltage switchincluded iu a controlling-circuit of the apparatus,electrically-actuated means for controlling said switch, a notched diskon the shaft of the rheostat-switch and a latch carried by theno-voltage7 switch and-adapted to cooperate with said notched disk tolock said no-Voltage switch open.

28. In an electric controller, the combination with a rheostat-switch, ashaft carrying means for operating said switch, a no-voltage switch andelectrical means for controlling the latter, of a notched disk on saidshaft, a shaft projecting from the no-voltage77 switch, and a latchcarried by said shaft and adapted to cooperate with the disk on therheostat-switch-operating shaft for locking said 11o-voltage switchopen.

29. In an electrical controller, the combination with a rheostat-switch,a shaft carrying means for operating said switch and a notched disksecured to said shaft, of a rockshaft, a switch-arm secured to one endof said shaft, two contacts, one of which is carried by the switch-arm,an electromagnet included in a controlling-circuit of the apparatus forcontrolling the movement of the switch-arm, a housing secured to theother end of said rock-shaft, and a spring-actuated latch carried bysaid housing and arranged to coperate with the notched disk to lock saidswitcharm with the contacts separated.

30. The combination with an electric controller, of a no-voltage switch,means for locking said switch open, means for releasing IIO troller, ofa normally closed no-voltage switch, a normally closed overload-switch,means for locking said switches open, and means operating toautomatically close said switches when they shall have been unlocked.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

WILLIAM K. LIGGETT. Witnesses:

W. T. GUY, W. G. MCPECK.

